1. Field of the Invention
The present invention relates to a lithography simulation method.
2. Description of the Related Art
Advance in scale-reduction of a mask pattern (mask layout) has made, and thereby, it is difficult to secure lithography simulation accuracy.
For example, a large difference occurs between the following two simulation results (e.g., see “Proc. SPIE2005, vol. 5754, p. 383-394, March 2005). One is a simulation result obtained by a thin mask approximation model. Another is a simulation result obtained by strict calculation considering mask topography effect. Therefore, the following strict calculation needs to make high accuracy simulation. Specifically, a strict calculation must be made considering the mask topography effect, that is, an electromagnetic field in the vicinity of a mask. However, if the strict calculation considering the mask topography effect is made, there is a problem that a large number of calculations are required.
As a result, it is conventionally difficult to carry out high accuracy lithography simulation considering the mask topography effect using a simple method.